Windows 2000 only supported standard format. It is group of legitimate keys, subkeys, and important in the registry that supports the files and contains backups of its data is called registry. On versions of Windows that support the latest format, the following hives still use the standard format: HKEY_CURRENT_USER, HKEY_LOCAL_MACHINE\SAM, HKEY_LOCAL_MACHINE\Security, and HKEY_USERS\.DEFAULT; all other hives use the latest format.